Bounce Back Distribtion Group

Hello,

I've a problem with bounce back when i send a mail with a distribution group and the recipent address is faulse, i don't receive the bounce back.
technical context :
2 Exchange server 2016 standard without edge in DAG
Antispam Exchange ENABLED
my external mail are filtred by an antispam gateway

Diagnostic:
My antispam gateway send me the bounce back, my server1 create event HARECEIVE the mail and create an event HADISCARD and the mail is DROP by the server1 or the server2.
do you have already meet this case ?

I don't use a filter spams (exchange antispam is configured by default) also i add the domain who give me the bounce back in white list, but it doesn't work.
For more information, if i send a mail with my personnal address to a bad address, i receive the bounce back without problem.
So if i send with the DG (i'm member and owner) i never receive the bounce back.
I see in the log my external antispam gateway send me the bounce back and the mail is lost/drop beetwen my 2 servers.